CN114389661B

CN114389661B - Channel measurement method and communication device

Info

Publication number: CN114389661B
Application number: CN202011141660.3A
Authority: CN
Inventors: 孟鑫; 杨烨
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-10-22
Filing date: 2020-10-22
Publication date: 2022-11-22
Anticipated expiration: 2040-10-22
Also published as: CN114389661A; EP4224731A1; EP4224731A4; US20230261704A1; WO2022083307A1

Abstract

The application provides a channel measurement method and a communication device. The method comprises the following steps: receiving a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit, wherein the plurality of reference signals are respectively precoded by precoding matrixes corresponding to the first frequency domain units, and the precoding matrixes corresponding to at least two different first frequency domain units in the plurality of first frequency domain units are different; generating a PMI based on the plurality of reference signals, the PMI being used to indicate a plurality of codewords corresponding to a plurality of second frequency domain units, the plurality of second frequency domain units belonging to the same frequency domain resource as the plurality of first frequency domain units, the plurality of codewords being used to determine a downlink channel; the PMI is transmitted. According to the method provided by the embodiment of the application, the accuracy of reconstructing the downlink channel can be improved.

Description

Channel measurement method and communication device

Technical Field

The present application relates to the field of communications, and more particularly, to a method for channel measurement and a communication device.

Background

In a large-scale multiple-input multiple-output (Massive MIMO) technology, a network device can reduce interference among multiple users and interference among multiple signal streams of the same user through precoding, which is beneficial to improving signal quality, realizing space division multiplexing and improving spectrum utilization rate.

At present, there is known a channel measurement method, in which a network device sends a downlink channel state information reference signal (CSI-RS), a terminal device estimates a downlink channel according to the received downlink CSI-RS, then selects a codeword that best matches the downlink channel from a predefined codebook set, and finally feeds back the selected codeword to the network device through an uplink channel. However, limited by the feedback overhead, the codebook set is usually in a discrete finite state, and the real channel is usually in an infinite continuous state, so that there is an inevitable quantization error between the codebook and the real channel, which becomes a bottleneck for restricting the network device to improve the accuracy of the downlink Channel State Information (CSI).

Disclosure of Invention

The application provides a channel measurement method and a communication device, which can determine a downlink channel by combining codebook feedback on a plurality of time-frequency blocks, and improve the accuracy of determining the downlink channel.

In a first aspect, a method for channel measurement is provided, which may include: receiving a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit, wherein the plurality of reference signals are respectively precoded by precoding matrixes corresponding to the first frequency domain units, and the precoding matrixes corresponding to at least two different first frequency domain units in the plurality of first frequency domain units are different; generating a pre-coding matrix indicator (PMI) based on the plurality of reference signals, the PMI being configured to indicate a plurality of codewords corresponding to a plurality of second frequency domain units, the plurality of second frequency domain units belonging to a same frequency domain resource as the plurality of first frequency domain units, the plurality of codewords being used to determine a downlink channel; the PMI is transmitted.

Based on the above technical solution, by loading different precoding matrices to the reference signals on at least two different frequency domain units on the same time domain unit, the correlation of the channels on different frequency domain units can be reduced, and further the correlation of the error of the terminal device performing quantization feedback on the codewords on different frequency domain units can be reduced, so that the accuracy of reconstructing the downlink channel can be improved.

In a second aspect, a method of channel measurement is provided, which may include: sending a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit, wherein the plurality of reference signals are respectively precoded by precoding matrixes corresponding to the first frequency domain units, and the precoding matrixes corresponding to at least two different first frequency domain units in the plurality of first frequency domain units are different; receiving a PMI, wherein the PMI is used for indicating a plurality of code words corresponding to a plurality of second frequency domain units, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource; and determining a downlink channel according to the plurality of code words and the space frequency domain channel characteristic matrix of the uplink channel.

The space frequency domain channel characteristic matrix of the uplink channel is determined according to the channel matrix of the uplink channel and the conjugate transpose of the channel matrix.

The time domain unit may be a radio frame (frame), a sub-frame (sub-frame), a slot (slot), or the like.

The first frequency domain unit may be a subband, a Resource Block (RB), a Resource Block Group (RBG), a precoding resource block group (PRG), and the like.

The second frequency domain unit may be a subband, an RB, an RBG, a PRG, etc.

For example, if the first frequency domain unit is a sub-band, different precoding matrices may be loaded to the reference signals on at least two different sub-bands on the same time domain unit. Accordingly, the second frequency domain unit may be an RB, i.e., the terminal device may perform codebook quantization feedback based on the RB; the second frequency domain unit may also be a subband, i.e., the terminal device may perform codebook quantization feedback based on the subband.

The frequency domain resources may be RBs, or RBGs, or predefined subbands (subbands), or frequency bands (bands), or bandwidth parts (BWPs), or Component Carriers (CCs).

The plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource, and it can be understood that the frequency domain resource composed of the plurality of second frequency domain units is the same as the frequency domain resource composed of the plurality of first frequency domain units. For example, if the first frequency domain unit is RB, the second frequency domain unit is RBG, and if the number of the first frequency domain units is 12, the frequency domain resource composed of a plurality of the first frequency domain units is 12 RBs, which are denoted as RB #1 to RB #12; accordingly, the frequency domain resources composed of the plurality of second frequency domain units are also 12 RBs, RB #1-RB #12. For another example, if the bandwidth of the first plurality of frequency domain elements is 15Hz, the bandwidth of the second plurality of frequency domain elements is also 15Hz.

With reference to the second aspect, in some implementations of the second aspect, the determining a downlink channel according to the codeword and a space-frequency domain channel feature matrix of an uplink channel includes: obtaining a first downlink channel according to the code word and the space frequency domain channel characteristic matrix, wherein the first downlink channel is an angle time delay domain channel; and obtaining a second downlink channel according to the first downlink channel and the space frequency domain channel characteristic matrix, wherein the second downlink channel is a space frequency domain channel.

Based on the technical scheme, the downlink channel is reconstructed by combining codebook feedback on a plurality of time-frequency blocks in the angle time delay domain by utilizing the sparsity of the downlink channel in the angle time delay domain, and then the channel in the angle time delay domain is transformed to the spatial frequency domain, so that the complexity of the reconstructed downlink channel can be reduced, and the performance of the reconstructed downlink channel can be improved.

With reference to the first aspect or the second aspect, in some implementations of the first aspect or the second aspect, precoding matrices corresponding to any two different first frequency domain units are different.

With reference to the first aspect or the second aspect, in certain implementations of the first aspect or the second aspect, the plurality of first frequency domain units are divided into at least two frequency domain unit groups, and precoding matrices corresponding to the at least two frequency domain unit groups are different.

For example, the first frequency domain unit is an RB and the groups of frequency domain units are subbands.

With reference to the first aspect or the second aspect, in some implementations of the first aspect or the second aspect, precoding matrices corresponding to any two different frequency domain unit groups are different.

With reference to the first aspect or the second aspect, in certain implementations of the first aspect or the second aspect, the precoding matrix is a random semi-unitary matrix.

With reference to the first aspect or the second aspect, in certain implementations of the first aspect or the second aspect, the precoding matrix is a product of a fixed beam matrix, which is a semi-unitary matrix with different columns having the same beam pattern, and a Mutual Unbiased Basis (MUB) matrix.

In a third aspect, a method for channel measurement is provided, which may include: receiving a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit; generating a PMI based on the plurality of reference signals and the weighting matrix, where the PMI is used to indicate a plurality of codewords corresponding to the weighted equivalent channels of the plurality of second frequency domain units, the plurality of codewords are used to determine a downlink channel, the weighted equivalent channel of each second frequency domain unit is obtained according to the weighting matrix corresponding to the second frequency domain unit, the weighting matrices corresponding to at least two different second frequency domain units in the plurality of second frequency domain units are different, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource; the PMI is transmitted.

Based on the above technical solution, by loading different weighting matrices to equivalent channels of at least two different second frequency domain units, the correlation of channels in different second frequency domain units can be reduced, and further the correlation of errors in quantization feedback performed by the terminal device on codewords in different second frequency domain units can be reduced, so that the accuracy of reconstructing a downlink channel can be improved.

In a fourth aspect, a method of channel measurement is provided, which may include: transmitting a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit; receiving a PMI, wherein the PMI is used for indicating a plurality of code words corresponding to weighted equivalent channels of a plurality of second frequency domain units, the plurality of code words are used for determining a downlink channel, the weighted equivalent channel of each second frequency domain unit is obtained according to a weighting matrix corresponding to the second frequency domain unit, the weighting matrices corresponding to at least two different second frequency domain units in the plurality of second frequency domain units are different, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource; and determining a downlink channel according to the plurality of code words and the space frequency domain channel characteristic matrix of the uplink channel.

Based on the above technical solution, by loading different weighting matrices to equivalent channels of at least two different second frequency domain units, correlations of channels in different second frequency domain units can be reduced, and further correlations of errors of quantization feedback of the terminal device on codewords in different second frequency domain units can be reduced, so that accuracy of reconstructing a downlink channel can be improved.

The time domain unit may be a radio frame, a subframe, a slot, etc.

The first frequency domain unit may be a subband, RB, RBG, PRG, etc.

The second frequency domain unit may be a subband, an RB, an RBG, a PRG, etc.

For example, the second frequency domain unit may be an RB, that is, the terminal device may perform codebook quantization feedback based on the RB, and perform codebook quantization feedback based on weighted equivalent channels of respective RBs, where weighting matrices corresponding to at least two RBs are different; the second frequency domain unit may also be a sub-band, that is, the terminal device may perform codebook quantization feedback based on the sub-band, and perform codebook quantization feedback based on the weighted equivalent channel of each sub-band, where the corresponding weighting matrices of at least two sub-bands are different.

The frequency domain resources may be RBs, or RBGs, or predefined subbands (subbands), or frequency bands (bands), or BWPs, or CCs.

With reference to the fourth aspect, in some implementations of the fourth aspect, the determining a downlink channel according to the multiple codewords and the space-frequency domain channel feature matrix of the uplink channel includes: obtaining a first downlink channel according to the plurality of code words and the space frequency domain channel characteristic matrix, wherein the first downlink channel is an angle time delay domain channel; and obtaining a second downlink channel according to the first downlink channel and the space frequency domain channel characteristic matrix, wherein the second downlink channel is a space frequency domain channel.

With reference to the third or fourth aspect, in some implementations of the third or fourth aspect, the corresponding weighting matrices of any two different second frequency-domain units are different.

With reference to the third or fourth aspect, in certain implementations of the third or fourth aspect, the plurality of second frequency-domain units are divided into at least two frequency-domain unit groups, and corresponding weighting matrices of at least two different frequency-domain unit groups are different.

For example, the second frequency-domain unit is an RB and the groups of frequency-domain units are subbands.

With reference to the third or fourth aspect, in certain implementations of the third or fourth aspect, the corresponding weighting matrices of any two different groups of frequency domain units are different.

With reference to the third or fourth aspect, in certain implementations of the third or fourth aspect, the plurality of reference signals are each precoded by a fixed beam matrix, the fixed beam matrix being a semi-unitary matrix with different columns having the same beam pattern; the weighting matrix is a MUB matrix.

In a fifth aspect, a communication apparatus is provided, which may be a terminal device, or a component in a terminal device. The communication device may comprise means for performing the method of the first aspect or the third aspect and any one of the possible implementations of the first aspect or the third aspect.

In a sixth aspect, a communications apparatus is provided that includes a processor. The processor is coupled to the memory and is configured to execute the instructions in the memory to implement the method in the first aspect or the third aspect and any possible implementation manner of the first aspect or the third aspect. Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a communication interface, the processor being coupled to the communication interface for inputting and/or outputting information, the information comprising at least one of instructions and data.

In one implementation, the communication device is a terminal device. When the communication device is a terminal device, the communication interface may be a transceiver, or an input/output interface.

Alternatively, the transceiver may be a transmit-receive circuit. Alternatively, the input/output interface may be an input/output circuit.

In another implementation, the communication device is a chip or a system of chips configured in the terminal equipment. When the communication device is a chip or a chip system configured in a terminal device, the communication interface may be an input/output interface, an interface circuit, an output circuit, an input circuit, a pin or a related circuit, and the like. The processor may also be embodied as a processing circuit or a logic circuit.

In a seventh aspect, a communication apparatus is provided, which may be a network device or a component in a network device. The communication device may comprise means for performing the method of the second or fourth aspect and any of its possible implementations.

In an eighth aspect, a communications apparatus is provided that includes a processor. The processor is coupled to the memory and is operable to execute the instructions in the memory to implement the method of the second or fourth aspect and any possible implementation of the second or fourth aspect. Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a communication interface, the processor being coupled to the communication interface for inputting and/or outputting information, the information comprising at least one of instructions and data.

In one implementation, the communication device is a network device. When the communication device is a network device, the communication interface may be a transceiver, or an input/output interface.

In another implementation, the communication device is a chip or a system of chips configured in the network device. When the communication device is a chip or a chip system configured in a network device, the communication interface may be an input/output interface, an interface circuit, an output circuit, an input circuit, a pin or a related circuit, and the like. The processor may also be embodied as a processing circuit or a logic circuit.

In a ninth aspect, there is provided a processor comprising: input circuit, output circuit and processing circuit. The processing circuit is configured to receive a signal through the input circuit and transmit a signal through the output circuit, so that the processor performs the method in any one of the possible implementations of the first aspect to the fourth aspect.

In a specific implementation process, the processor may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a flip-flop, various logic circuits, and the like. The input signal received by the input circuit may be received and input by, for example, but not limited to, a receiver, the signal output by the output circuit may be, for example, but not limited to, output to and transmitted by a transmitter, and the input circuit and the output circuit may be the same circuit that functions as the input circuit and the output circuit, respectively, at different times. The embodiment of the present application does not limit the specific implementation manner of the processor and various circuits.

In a tenth aspect, a processing apparatus is provided that includes a communication interface and a processor. The communication interface is coupled with the processor. The communication interface is used for inputting and/or outputting information. The information includes at least one of instructions and data. The processor is configured to execute a computer program to cause the processing apparatus to perform the method of any one of the possible implementations of the first aspect to the fourth aspect.

Optionally, the number of the processors is one or more, and the number of the memories is one or more.

In an eleventh aspect, a processing apparatus is provided that includes a processor and a memory. The processor is configured to read instructions stored in the memory, and may receive a signal via the receiver and transmit a signal via the transmitter, so that the processing device performs the method of any one of the possible implementations of the first aspect to the fourth aspect.

Alternatively, the memory may be integral to the processor or provided separately from the processor.

In a specific implementation process, the memory may be a non-transitory (non-transitory) memory, such as a Read Only Memory (ROM), which may be integrated on the same chip as the processor, or may be separately disposed on different chips, and the embodiment of the present application does not limit the type of the memory and the arrangement manner of the memory and the processor.

It will be appreciated that the associated information interaction process, for example, the process of sending the indication information may be the process of outputting the indication information from the processor, and the process of receiving the indication information may be the process of inputting the received indication information to the processor. In particular, the information output by the processor may be output to a transmitter and the input information received by the processor may be from a receiver. The transmitter and receiver may be collectively referred to as a transceiver, among others.

The apparatus in the tenth and eleventh aspects may be a chip, the processor may be implemented by hardware or may be implemented by software, and when implemented by hardware, the processor may be a logic circuit, an integrated circuit, or the like; when implemented in software, the processor may be a general-purpose processor implemented by reading software code stored in a memory, which may be integrated with the processor, located external to the processor, or stand-alone.

In a twelfth aspect, there is provided a computer program product comprising: a computer program (which may also be referred to as code, or instructions), which when executed, causes a computer to perform the method of any one of the possible implementations of the first to fourth aspects described above.

In a thirteenth aspect, a computer-readable medium is provided, which stores a computer program (which may also be referred to as code or instructions) that, when executed on a computer, causes the computer to perform the method of any one of the possible implementations of the first to fourth aspects.

In a fourteenth aspect, a communication system is provided, which includes the terminal device and the network device.

Drawings

Fig. 1 is a schematic diagram of a communication system suitable for use in the method of channel measurement of the embodiments of the present application.

Fig. 2 is a schematic flowchart of a channel measurement method provided in an embodiment of the present application.

Fig. 3 to fig. 5 are schematic diagrams illustrating mapping of reference signals in time frequency resources according to an embodiment of the present disclosure.

Fig. 6 is a schematic flow chart of a channel measurement method according to another embodiment of the present application.

Fig. 7 is a schematic block diagram of a communication device provided in an embodiment of the present application.

Fig. 8 is another schematic block diagram of a communication device provided in an embodiment of the present application.

Fig. 9 is a schematic structural diagram of a terminal device provided in an embodiment of the present application.

Fig. 10 is a schematic structural diagram of a network device according to an embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The technical scheme provided by the application can be applied to various communication systems, such as: long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD), universal Mobile Telecommunications System (UMTS), worldwide Interoperability for Microwave Access (WiMAX) communication system, and fifth generation (5) ^th Generation, 5G) mobile communication system or new radio access technology (NR). The 5G mobile communication system may include a non-standalone (NAS) network and/or a Standalone (SA) network, among others.

The technical scheme provided by the application can also be applied to Machine Type Communication (MTC), long Term Evolution-machine (LTE-M) communication between machines, device to device (D2D) network, machine to machine (M2M) network, internet of things (IoT) network, or other networks. Wherein the IoT network may comprise, for example, a car networking network. The communication modes in the car networking system are collectively referred to as car-to-other devices (V2X, X may represent anything), for example, the V2X may include: vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) or vehicle to network (V2N) communication, and the like.

The technical scheme provided by the application can also be applied to future communication systems, such as a sixth generation mobile communication system and the like. This is not a limitation of the present application.

In the embodiment of the present application, the network device may be any device having a wireless transceiving function. Such devices include, but are not limited to: an evolved Node B (eNB), a Radio Network Controller (RNC), a Node B (NB), a Base Station Controller (BSC), a base transceiver station (base transceiver station, BTS), a home base station (e.g., home evolved Node B, or home Node B, HNB), a Base Band Unit (BBU), an Access Point (AP) in a wireless fidelity (WiFi) system, a wireless relay Node, a wireless backhaul Node, a Transmission Point (TP), or a Transmission and Reception Point (TRP), etc., and may also be 5G, e.g., NR, a system NB, or a transmission point (trptp), one or a group (including multiple antennas) of a base station in a 5G system may also be a panel, or a panel, e.g., a Radio Network Controller (RNC), a base station (base station) in a distributed Node B, or BBU, and the like.

In some deployments, the gNB may include a Centralized Unit (CU) and a DU. The gNB may also include an Active Antenna Unit (AAU). The CU implements part of the function of the gNB, and the DU implements part of the function of the gNB, for example, the CU is responsible for processing non-real-time protocols and services, and implementing functions of a Radio Resource Control (RRC) layer and a packet data convergence layer (PDCP) layer. The DU is responsible for processing a physical layer protocol and a real-time service, and implements functions of a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a Physical (PHY) layer. The AAU implements part of the physical layer processing functions, radio frequency processing and active antenna related functions. Since the information of the RRC layer eventually becomes or is converted from the information of the PHY layer, the higher layer signaling, such as RRC layer signaling, can also be considered as being transmitted by the DU or by the DU + AAU under this architecture. It will be appreciated that the network devices may include devices of one or more of the CU nodes, DU nodes, AAU nodes. In addition, the CU may be divided into network devices in an access network (RAN), or may be divided into network devices in a Core Network (CN), which is not limited in this application.

The network device provides a service for a cell, and a terminal device communicates with the cell through a transmission resource (e.g., a frequency domain resource, or a spectrum resource) allocated by the network device, where the cell may belong to a macro base station (e.g., a macro eNB or a macro gNB), or may belong to a base station corresponding to a small cell (small cell), where the small cell may include: urban cell (metro cell), micro cell (microcell), pico cell (pico cell), femto cell (femto cell), etc., and these small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-rate data transmission service.

In an embodiment of the present application, a terminal device may also be referred to as a User Equipment (UE), an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment.

The terminal device may be a device providing voice/data connectivity to a user, e.g. a handheld device, a vehicle mounted device, etc. with wireless connection capability. Currently, some examples of terminals may be: a mobile phone (mobile phone), a tablet computer (pad), a computer with wireless transceiving function (e.g. a laptop, a palmtop, etc.), a Mobile Internet Device (MID), a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote medical (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a cellular phone, a cordless phone, a session initiation protocol (session initiation protocol) phone, a wireless local loop (SIP) phone, a wireless local loop (wireless local), a wireless local home (smart home), a wireless terminal in public network (wireless local), a wireless network (wireless local) device, a wireless network (wireless network) device, a wireless network communication network (PDA) device, a wireless network communication network with wireless communication function, a wireless network communication network (wireless network) processing function, or other mobile network communication device with wireless network (PLMN) processing function.

The wearable device can also be called a wearable intelligent device, and is a general name of devices which are intelligently designed and can be worn by applying a wearable technology to daily wearing, such as glasses, gloves, watches, clothes, shoes and the like. A wearable device is a portable device that is worn directly on the body or integrated into the clothing or accessories of the user. The wearable device is not only a hardware device, but also realizes powerful functions through software support, data interaction and cloud interaction. The generalized wearable smart device includes full functionality, large size, and can implement full or partial functionality without relying on a smart phone, such as: smart watches or smart glasses and the like, and only focus on a certain type of application function, and need to be matched with other equipment such as a smart phone for use, such as various smart bracelets for physical sign monitoring, smart jewelry and the like.

In addition, the terminal device may also be a terminal device in an internet of things (IoT) system. The IoT is an important component of future information technology development, and is mainly technically characterized in that articles are connected with a network through a communication technology, so that an intelligent network with man-machine interconnection and object interconnection is realized. The IoT technology can achieve massive connection, deep coverage, and power saving of the terminal through, for example, narrowband (NB) technology.

In addition, the terminal equipment can also comprise sensors such as an intelligent printer, a train detector, a gas station and the like, and the main functions of the terminal equipment comprise data collection (part of the terminal equipment), control information and downlink data receiving of the network equipment, electromagnetic wave sending and uplink data transmission to the network equipment.

For the understanding of the embodiments of the present application, a communication system suitable for the channel measurement method provided in the embodiments of the present application will be described in detail with reference to fig. 1. Fig. 1 shows a schematic diagram of a communication system 100 suitable for use in the method provided by the embodiments of the present application. As shown, the communication system 100 may include at least one network device, such as the network device 101 shown in fig. 1; the communication system 100 may further comprise at least one terminal device, such as the terminal devices 102 to 107 shown in fig. 1. The terminal devices 102 to 107 may be mobile or stationary. Network device 101 and one or more of terminal devices 102-107 may each communicate over a wireless link. Each network device may provide communication coverage for a particular geographic area and may communicate with terminal devices located within that coverage area. For example, the network device may send configuration information to the terminal device, and the terminal device may send uplink data to the network device based on the configuration information; for another example, the network device may send downlink data to the terminal device. Thus, the network device 101 and the terminal devices 102 to 107 in fig. 1 constitute one communication system.

Alternatively, the terminal devices may communicate directly with each other. For example, direct communication between terminal devices may be implemented by using D2D technology, etc., and

terminal devices

105 and 106 in the figure may communicate with network device 101 directly; it may also communicate indirectly with the network device 101, such as terminal device 107 communicating with the network device 101 via terminal device 105.

It should be understood that fig. 1 exemplarily shows one network device and a plurality of terminal devices, and communication links between the respective communication devices. Alternatively, the communication system 100 may include a plurality of network devices, and each network device may include other numbers of terminal devices within its coverage area, such as more or fewer terminal devices. This is not limited in this application.

The above-described respective communication devices, such as the network device 101 and the terminal devices 102 to 107 in fig. 1, may be configured with a plurality of antennas. The plurality of antennas may include at least one transmit antenna for transmitting signals and at least one receive antenna for receiving signals. Additionally, each communication device can additionally include a transmitter chain and a receiver chain, each of which can comprise a plurality of components associated with signal transmission and reception (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, antennas, etc.), as will be appreciated by one skilled in the art. Therefore, the network equipment and the terminal equipment can communicate through the multi-antenna technology.

Optionally, the wireless communication system 100 may further include other network entities such as a network controller, a mobility management entity, and the like, which is not limited thereto.

The multi-antenna system is provided with a plurality of receiving and transmitting antennas on network equipment, and the capacity of the system is improved by exploring and utilizing space dimension resources. A key factor for improving the downlink capacity of the multi-antenna system is to acquire more accurate downlink Channel State Information (CSI) at the network device. Because the channel-calibrated TDD system has reciprocity between uplink and downlink channels, the downlink CSI can be estimated by using an uplink sounding signal (SRS) sent by a user. In the FDD system, the uplink and downlink frequency band difference exists, and the channel reciprocity does not exist, so that the downlink CSI can only be fed back to the network device by the terminal device. In addition, if the channel of the TDD system is not calibrated, the equivalent baseband channel between the network device and the terminal device also has no reciprocity, and therefore, the downlink CSI also needs to be fed back to the network device by the terminal device.

In the downlink CSI feedback process, the network device first sends a downlink channel state information reference signal (CSI-RS); the terminal equipment estimates a downlink channel according to the received downlink CSI-RS, selects a code word which is most matched with the downlink channel from a predefined codebook set, and finally feeds back the selected code word to the network equipment through the uplink channel. Due to the limitation of uplink feedback overhead, the codebook set is usually in a discrete finite state, and the real channel is usually in a continuous infinite state, so that an inevitable quantization error exists between the codebook and the real channel, which becomes a bottleneck for restricting the network equipment end from improving the accuracy of the downlink CSI. Since the wireless channel generally has time correlation and frequency correlation, codebook feedback on multiple time frequency blocks can be jointly utilized at the network device side to jointly reconstruct the channel on the time frequency blocks, so as to improve CSI accuracy.

One existing scheme for reconstructing a downlink channel by using time correlation of channels is as follows: when the network equipment sends the CSI-RS, the CSI-RS is weighted by using a pilot frequency weighting matrix, the weighting matrix is changed among different moments (CSI-RS subframes), and the weighting matrices on all Resource Blocks (RBs) in the same CSI-RS subframe are the same; the terminal equipment carries out channel estimation according to the received downlink CSI-RS, obtains a channel estimation result which is an equivalent channel of a real channel after weighting, carries out codebook quantization on the equivalent channel and feeds back a codebook to the network equipment; and the network equipment reconstructs the real downlink CSI by combining the pilot weighting matrix fed back by the terminal equipment each time. The downlink CSI reconstructed by the network device may be used for downlink multiuser scheduling, beamforming transmission, and the like.

Since the above channel reconstruction scheme only uses the time correlation of the channel in principle, but does not use the frequency correlation of the channel, even if the terminal device performs subband feedback, the network device reconstructs each subband channel independently, but does not perform joint reconstruction between subbands, so there is a space for performance improvement. In addition, when the network equipment transmits the CSI-RS, the same weighting matrix is used in the whole band, even if the terminal equipment adopts sub-band feedback, the correlation of codebook quantization errors among the sub-bands is high, and therefore, the network equipment cannot bring about gains when carrying out the joint reconstruction among the sub-bands.

In view of this, embodiments of the present application provide a channel measurement method, so as to improve accuracy of a network device reconstructing a downlink channel.

The method provided by the embodiment of the application will be described in detail below with reference to the accompanying drawings.

It should be understood that the method provided by the embodiment of the present application is described in detail below by taking the interaction between the terminal device and the network device as an example, for convenience of understanding and description only. This should not constitute any limitation on the subject matter for which methods provided herein are performed. For example, the terminal device shown in the following embodiments may be replaced by a component (such as a circuit, a chip, or a system of chips) in the configuration and terminal device. The network device shown in the downstream embodiment may also be replaced by a component (such as a circuit, a chip, or a system of chips) configured in the network device.

The embodiments shown below do not particularly limit the specific structure of the execution subject of the method provided by the embodiments of the present application, as long as the communication can be performed according to the method provided by the embodiments of the present application by running the program recorded with the codes of the method provided by the embodiments of the present application, for example, the execution subject of the method provided by the embodiments of the present application may be a terminal device or a network device, or a functional module capable of calling the program and executing the program in the terminal device or the network device.

The following describes the channel measurement method provided by the embodiments of the present application in detail with reference to the accompanying drawings. Fig. 2 is a schematic flow chart diagram of a method 200 for channel measurement provided by an embodiment of the present application. As shown in fig. 2, the method 200 may include S210 to S260. The steps in method 200 are described in detail below.

S210, the terminal equipment sends the uplink reference signal. Accordingly, in S210, the network device receives an uplink reference signal.

An uplink reference signal sent by the terminal device to the network device may be used to measure an uplink channel, where the uplink reference signal may be a Sounding Reference Signal (SRS), or may be another reference signal, which is not limited in this embodiment of the present invention.

Specifically, the terminal device may periodically transmit the uplink reference signal to the network device.

And S220, the network equipment estimates an uplink channel according to the uplink reference signal and calculates a space frequency domain channel characteristic matrix of the uplink channel.

Specifically, the method for the network device to estimate the uplink channel according to the uplink reference signal may refer to the prior art, and for brevity, detailed description is not given in this embodiment of the present application.

A method for a network device to calculate a space-frequency domain channel feature matrix according to an estimated uplink channel is described below.

For the sake of understanding, assume that the number of antennas at the network device side is M _t The number of the antennas at the terminal equipment end is M _r The number of frequency domain units (in the example RB) is K. For the r-th transmitting antenna of the terminal device, the network device estimates that uplink channels of all antennas from the r-th transmitting antenna to the network device in the k-th RB can be recorded as

Wherein K =1,2, …, K, r =1,2, …, M _r ，

Dimension of M _t X 1. It can be understood that each time the network device receives an uplink reference signal from the terminal device, one uplink reference signal can be calculated according to the uplink reference signal

As an example, the network device splices the r-th transmitting antenna of the terminal device to all antennas of the network device into a column vector in uplink channels of all RBs, which is denoted as

Where vec () represents a vectorization operation,

is of dimension M _t K is multiplied by 1. Further, the network device calculates

And carrying out statistical averaging on all transmitting antennas and time of the terminal equipment to obtain a long-term statistical space-frequency domain joint channel covariance matrix R of the terminal equipment, wherein the dimension of the R is M _t K×M _t K。

For example, if the terminal device has only one transmitting antenna, the network device will obtain a plurality of uplink reference signals from the terminal device within a period of time

And carrying out statistical averaging to obtain a long-term statistical space frequency domain combined channel covariance matrix R of the terminal equipment.

For another example, if the terminal device has multiple transmit antennas, the network device may first send the signals to the terminal device

Performing statistical averaging on all transmitting antennas of the terminal equipment to obtain

Further, the network device obtains a plurality of uplink reference signals from the terminal device within a period of time

It should be understood that the network devices described above will be

The method for performing statistical averaging on all transmitting antennas of the terminal device and time is only an example, and should not limit the embodiments of the present application. For example, the network device may further obtain a plurality of uplink reference signals from the terminal device over a period of time

A plurality of

Further, the network device calculates the low rank approximation of R to obtain the space frequency domain channel characteristic matrix P, that is, R ≈ PP ^H Dimension of P is M _t KxN, N is much less than M _t K. The prior art can be referred to for a method of calculating a low rank approximation of a matrix.

As another example, the network device splices the r-th transmitting antenna of the terminal device to all antennas of the network device in uplink channels of all RBs to form a matrix, which is denoted as

Is of dimension M _t And (ii) x K. Further, the network devices compute separately

And

and performing statistical averaging on all transmitting antennas and time of the terminal equipment to respectively obtain long-term statistical spatial domain channel covariance matrixes R of the terminal equipment _s Covariance matrix R with frequency domain channel _f ，R _s And R _f Are respectively M _t ×M _t And K.times.K.

Carrying out statistical averaging to obtain a long-term statistical space domain channel covariance matrix R of the terminal equipment _s (ii) a Obtaining a plurality of uplink reference signals from the terminal equipment in a period of time

Carrying out statistical averaging to obtain a long-term statistical frequency domain channel covariance matrix R of the terminal equipment _f 。

For another example, if the terminal device has multiple transmit antennas, the network device may first couple

Will be provided with

Carrying out statistical averaging to obtain a long-term statistical space domain channel covariance matrix R of the terminal equipment _s A plurality of uplink reference signals obtained from the terminal equipment in a period of time

It should be understood that the network devices described above will be

And

the method for performing statistical averaging on all the transmitting antennas of the terminal device and time is only an example, and should not limit the embodiments of the present application. For example, the network device may further obtain a plurality of uplink reference signals from the terminal device over a period of time

A plurality of

A plurality of

A plurality of

A plurality of

Further, the network devices calculate R separately _s And R _f Obtaining a space domain channel characteristic matrix P by low rank approximation _s And a frequency domain channel characteristic matrix P _f I.e. by

P _s Is of dimension M _t ×N _s ，P _f Is K × N _f (ii) a Further, the network device calculates the basis P _s And P _f Computing a space-frequency domain channel characteristic matrix P, i.e.

Dimension of P is M _t K×N，N＝N _s N _f . The prior art can be referred to for a method of calculating a low rank approximation of a matrix.

S230, the network device transmits a plurality of reference signals # a. Accordingly, in S230, the terminal device receives a plurality of reference signals # a.

The plurality of reference signals # a are reference signals in a plurality of first frequency domain units in the same time domain unit, and the time domain unit in which the plurality of reference signals # a are located is hereinafter referred to as time domain unit # a. The reference signals # A are precoded by the precoding matrix #1 corresponding to the first frequency domain unit where the reference signals # A are located respectively, and the precoding matrices #1 corresponding to at least two different first frequency domain units are different, that is, the reference signals # A carried on at least two different first frequency domain units are precoded by different precoding matrices #1.

Optionally, the corresponding precoding matrices #1 on any two different first frequency domain units are different, that is, the reference signal # a carried on any two different first frequency domain units is precoded by the different precoding matrices #1.

The time domain unit #1 may be a radio frame (frame), a subframe (sub-frame), a slot (slot), etc., which is not limited in this embodiment of the present application, and the time domain unit #1 is a subframe as an example for description.

The first frequency domain unit may be a subband, a Resource Block (RB), a Resource Block Group (RBG), a precoding resource block group (PRG), and the like, which is not limited in this embodiment.

Taking the first frequency domain unit as RB and the number of reference signals # a as K as an example, fig. 3 shows a mapping diagram of K reference signals # a on time domain resources. As shown in fig. 3, the reference signals # a (RS #1 to RS # K) are all carried on the time domain unit #1 (subframe # 1), and any two of the reference signals # a (RS #1 to RS # K) are reference signals on different RBs, for example, RS #1 is carried on RB #1, RS #2 is carried on RB #2, … …, and RS # K is carried on RB # K, i.e., any two of RS #1 to RS # K are reference signals on different RBs.

As shown in fig. 3, any two reference signals # a among the K reference signals # a are reference signals on different RBs. Moreover, at least two reference signals # a of the K reference signals # a have different precoding matrices #1. Record RS #1 sent by the network device on RB #1 as B ₁ X ₁ RS #2 transmitted on RB #2 is denoted as B ₂ X ₂ … …, RS # K transmitted over RB # K is denoted as B _K X _K Wherein X is _k And B _k Reference signals before precoding and precoding matrices #1, K =1,2, …, K corresponding to RS # K, respectively. X _k And B _k Are P × P and M, respectively _t X P, P denotes the number of ports of the reference signal # a. As can be seen from the above description, B ₁ ，B ₂ ，……，B _K Are not identical. It is understood that in the case of P =1, B _k Is of dimension M _t X 1, then B _k May be referred to as a precoding vector.

Alternatively, the precoding matrix #1 corresponding to any two reference signals # A among the K reference signals # A shown in FIG. 3 is different, namely B ₁ ，B ₂ ，……，B _K Any two of which are different.

As another example, the first frequency-domain units may be subbands. Taking the number of the reference signals # a as K as an example, fig. 4 shows a mapping diagram of the K reference signals # a on the time domain resource. As shown in fig. 4, the reference signals # a (RS #1 to RS # K) are all carried on the time domain unit #1 (subframe # 1), and at least two of the reference signals # a (RS #1 to RS # K) are reference signals on different subbands, for example, RS #1 is carried on the subband #1, and RS #3 is carried on the subband #2, i.e., RS #1 and RS #3 are reference signals on different subbands.

As shown in fig. 4, at least two reference signals # a of the K reference signals # a are reference signals on different subbands. Correspondingly, among the K reference signals # a, the precoding matrix #1 corresponding to the reference signal # a on at least two different subbands is different. For example, the precoding matrix #1 of sub-band #1 corresponding to the reference signal # a on sub-band #2 may be different, e.g., RS #1 and RS #3 are carried by sub-band #1 and sub-band #2, respectively, and B corresponding to RS #1 and RS #3, respectively ₁ And B ₃ Is different. In this case, the precoding matrix #1 corresponding to the reference signal # a in the subband #1 other than the subband #2 may be different from or the same as that in the subband #1, for example, the precoding matrix #1 corresponding to the reference signal # a in the subband #1 and the subband # M may be the same or different from each other; the subband #2 may be the same as or different from the precoding matrix #1 corresponding to the reference signal # a in the subband #1 other than the subband #1, and for example, the subband #2 may be the same as or different from the precoding matrix #1 corresponding to the reference signal # a in the subband # M.

It can be understood that in case of considering subband quantization, the precoding matrix #1 corresponding to the reference signal # a on different RBs on the same subband is the same. For example, when RS #1 and RS #2 are both carried in subband #1, B corresponding to RS #1 and RS #2 is assigned to B ₁ And B ₂ Are the same.

Alternatively, as shown in fig. 4, in the K reference signals # a, the precoding matrix #1 corresponding to the reference signal # a on any two different subbands is different.

It should be understood that fig. 4 only illustrates that one subband includes two RBs, and the number of RBs included in one subband may be different in different system configurations.

The embodiment of the present application does not limit the specific form of the precoding matrix #1.

As an example, the precoding matrix #1 may be a random semi-unitary matrix denoted as Ψ.

For example, when the number of reference signals # A is K and the first frequency domain unit is RB, B _k Can be expressed as:

B _k ＝Ψ _k ，k＝1,2,…,K (1)

Ψ _k with a representation dimension of M _t Random semi-unitary matrices of x P, i.e. psi for different k _k Should be different.

For another example, when the number of reference signals # a is K and the first frequency domain element is a subband, B is considered when subband quantization is considered, that is, when precoding matrices #1 corresponding to reference signals # a on different RBs on the same subband are the same _k Can be expressed as:

B _k ＝Ψ _m ，k∈C _m ，m＝1,2,…,M (2)

wherein M is the number of subbands; Ψ _m With a representation dimension of M _t Random semi-unitary matrices of x P, i.e. Ψ for different m _m Should be different; c _m Denotes the set of RBs carrying reference Signal # A, C, contained in the mth subband ₁ ∪C ₂ ∪…∪C _M = {1,2, …, K }. As shown in FIG. 4, sub-band #1 contains reference signals # ARB of RB #1 and RB #2, then C ₁ =1,2; the RBs carrying reference signal # A included in subband #2 are RB #3 and RB #4, and C ₂ = 3,4; the set of RBs carrying reference signal # A contained in subband # M is RB # K-1 and RB # K, then C _M ＝{K-1，K}。

As another example, precoding matrix #1 may be a product of a fixed beam matrix and a Mutual Unbiased Bases (MUB) matrix. The fixed beam matrix may be a semi-unitary matrix with different columns having the same beam pattern, for example, a Discrete Fourier Transform (DFT) matrix, denoted as F, and a MUB matrix denoted as Φ.

B _k ＝FΦ _mod(k,P+1) ，k＝1,2,…,K (3)

{Φ ₀ ,Φ ₁ ,…,Φ _P denotes a set of MUB matrices with P +1 dimensions P × P, mod (a, b) denotes a modulo b operation on a.

For another example, if the number of reference signals # A is K and the first frequency domain element is a subband, B is _k Can be expressed as:

B _k ＝FΦ _mod(m,P+1) k∈C _m ,m＝1,2,…,M (4)

S240, the terminal device generates PMI #1.

S250, the terminal device transmits PMI #1. Accordingly, in S250, the network device receives PMI #1.

PMI #1 is determined by the terminal apparatus based on the received plurality of reference signals # a. The PMI #1 is configured to indicate a plurality of codewords #1, the plurality of codewords #1 correspond to a plurality of second frequency domain units one to one, the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource, and the plurality of codewords #1 are configured to determine a downlink channel. The one-to-one correspondence of the plurality of codewords #1 with the plurality of second frequency domain units may be understood as that each codeword #1 is obtained by the terminal device based on the reference signal # a on the second frequency domain unit.

The second frequency domain unit may be a subband, an RB, an RBG, a PRG, etc., which is not limited in this embodiment.

The frequency domain resource may be an RB, or an RBG, or a predefined subband (subband), or a band (band), or a BWP, or a CC.

The plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource, and it can be understood that the frequency domain resource composed of the plurality of second frequency domain units is the same as the frequency domain resource composed of the plurality of first frequency domain units. For example, if the first frequency domain unit is RB, the second frequency domain unit is RBG, and if the number of the first frequency domain units is 12, the frequency domain resource composed of a plurality of the first frequency domain units is 12 RBs, which are denoted as RB #1 to RB #12; accordingly, the frequency domain resources composed of the plurality of second frequency domain units are also 12 RBs, RB #1-RB #12. For another example, if the bandwidth formed by the first plurality of frequency domain elements is 15Hz, the bandwidth formed by the second plurality of frequency domain elements is also 15Hz.

The second frequency domain unit is an RB as an example and is explained below. That is, the following description will be given taking as an example that the terminal device obtains the codeword #1 based on the reference signal # a received on each RB.

After receiving the plurality of reference signals # a transmitted by the network device, the terminal device may measure the downlink channel according to the plurality of reference signals # a and estimate the equivalent channel of each RB. The method for estimating the equivalent channel of each RB by the terminal device is not limited in the embodiment of the present application, for example, the terminal device may estimate the equivalent channel of each RB by using a Least Square (LS) method.

For example, for the kth reference signal # a transmitted by the network device, the signal received by the terminal device may be represented as:

Y _k ＝H _dl,k B _k X _k +Z _k ，k＝1,2,…,K (5)

wherein H _dl,k Represents a downlink channel on the k RB with dimension M _r ×M _t ；Z _k The representation represents interference noise with a dimension M _r X P. The equivalent channel H of the kth RB can be obtained according to the formula (5) _dl,k B _k LS of (is) estimated as Y _k X _k ^-1 。

Alternatively, in the case that the first frequency domain unit is a subband, according to the above description, the precoding matrices #1 corresponding to all reference signals # a in the same subband are the same, and therefore, the terminal device may also perform the joint filtering and denoising processing on the LS estimation results of all RBs in the same subband, and finally obtain the equivalent noise on the kth RBThe channel can be represented as

The embodiment of the present application does not limit the specific method of the combined filtering and denoising process.

Further, the terminal device may determine the codeword #1 corresponding to each RB according to the equivalent channel of each RB, and feed back to the network device through the PMI #1.

The embodiment of the present application does not limit the method for determining the codeword #1 of each RB according to the equivalent channel of each RB by the terminal device. For example, the terminal device may perform Singular Value Decomposition (SVD) on the equivalent channel of each RB, and determine codeword #1 of each RB. In codeword #1 of one RB, each column may correspond to one transport layer. Let the k RB codeword #1 be J _k The dimension is P multiplied by R, and R is the number of transmission layers. It can be understood that in the case where the precoding matrix #1 corresponding to the reference signal # a on each RB is different, quantization feedback of the codeword #1 of each RB should be independently performed.

Optionally, the terminal device may also perform quantization feedback based on the sub-bands, i.e., the second frequency domain unit may be a sub-band. The terminal equipment can determine the equivalent channel of the sub-band according to the equivalent channels of all RBs in one sub-band; the codeword #1 of the subband is further determined from the equivalent channel of the subband. Likewise, in codeword #1 for one subband, each column may correspond to one transmission layer. Let the codeword #1 of the mth subband be W _m The dimension is P multiplied by R, and R is the number of transmission layers. It can be understood that, in the case where the precoding matrix #1 corresponding to the reference signal # a on each subband is different, quantization feedback of the codeword #1 of each subband should be performed independently.

The embodiment of the present application does not limit the manner in which the terminal device feeds back the codeword #1 of each RB to the network device through the PMI #1.

For example, the terminal device may transmit a plurality of PMIs #1 to the network device, each PMI #1 indicating a codeword #1 of one RB. For another example, the terminal device may transmit one PMI #1 to the network device, the one PMI #1 indicating the codeword #1 of each RB.

The embodiment of the present application does not limit the way in which the terminal device determines PMI #1. For example, the terminal device may determine the PMI based on the port selection codebook. The port selection codebook may be, for example, a type II port selection codebook (type II port selection codebook) defined in the NR protocol. For more ways for the terminal device to determine PMI #1, reference may be made to the prior art, and for brevity, details of embodiments of the present application are not described again.

Further, after receiving the PMI #1, the network device may determine codeword #1 of each RB according to the PMI #1.

And S260, the network equipment determines a downlink channel according to the code word #1 of each RB and the space frequency domain channel characteristic matrix of the uplink channel.

Order to

Wherein e is _k Represents a column vector having a dimension of K × 1, only the kth element being 1, and the remaining elements being 0,

the representation dimension is M _t ×M _t The unit matrix of (2).

Under the condition that the terminal equipment carries out quantization feedback based on sub-bands, J is enabled _k ＝W _m k∈C _m 。

Further, the network device may perform the following iterative operations:

wherein t _ larget _ eigvec () represents the first t largest eigenvectors, V _k,1 And with

Respectively represent

Left and right feature matrices, i.e. obtained by SVD decomposition

Iternum is the number of iterations, σ ² Are true parameters. And G obtained after iteration represents the reconstructed angle time delay domain channel. Finally, the network device obtains the space-frequency domain channel on each RB according to equation (6):

it should be understood that, in the process of determining the downlink channel, only the network device determines the downlink channel of each RB as an example for description, and the embodiment of the present application should not be limited in any way. For example, the above-mentioned iterative operation formula and formula (6) may be appropriately modified to determine the downlink channel of each subband.

In the embodiment of the present application, by loading different precoding matrices on reference signals in at least two different first frequency domain units in the same time domain unit, the correlation of channels in different frequency domain units can be reduced, and further, the correlation of errors in quantization feedback performed by terminal equipment on the codeword #1 in different frequency domain units can be reduced, so that the accuracy of reconstructing a downlink channel can be improved. In addition, according to the embodiment of the application, the downlink channel is jointly reconstructed in the angle delay domain by utilizing the sparsity of the downlink channel in the angle delay domain, and then the channel in the angle delay domain is transformed to the spatial frequency domain, so that the complexity of the reconstructed downlink channel can be reduced, and the performance of the reconstructed downlink channel can be improved.

Optionally, the method 200 may further include S270 to S290.

S270, the network device transmits a plurality of reference signals # B. Accordingly, in S270, the terminal device receives a plurality of reference signals # B.

The multiple reference signals # B are reference signals in multiple first frequency domain units in the same time domain unit, and the time domain unit in which the multiple reference signals # B are located is hereinafter referred to as time domain unit #2. The multiple reference signals # B are precoded by the precoding matrix #2 corresponding to the first frequency domain unit where the multiple reference signals # B are located, and the precoding matrices #2 corresponding to the at least two different first frequency domain units are different, that is, the reference signals # B carried on the at least two different first frequency domain units are precoded by the different precoding matrices #2.

Optionally, the precoding matrices #2 corresponding to any two different first frequency domain units are different, that is, the reference signals # a carried on any two different first frequency domain units are precoded by different precoding matrices #1.

For the mapping relationship of multiple reference signals # B on the time-frequency resource, reference may be made to the description of reference signal # a in S230, and for brevity, the detailed description is not repeated in this embodiment.

For the description of the precoding matrix #2, reference may be made to the description of the precoding matrix #1 in S230, and for brevity, the embodiment of the present application is not described in detail.

Time domain unit #2 is different from time domain unit #1.

The following describes the relationship between precoding matrix #1 and precoding matrix #2.

The embodiment of the present application does not limit the relationship between the precoding matrix #1 and the precoding matrix #2.

As an example, the precoding matrix #1 and the precoding matrix #2 corresponding to the reference signal # a and the reference signal # B, respectively, on the same frequency domain unit may be the same. The following description will be given taking the example where the first frequency domain unit is a subband.

For example, as shown in fig. 5, if RS #1,1 (an example of reference signal # a) and RS #2,1 (a first example of reference signal # B) are both reference signals on subband #1, precoding matrix #1 and precoding matrix #2 corresponding to

RS #

1,1 and

RS #

2,1, respectively, may be the same; for another example, when RS #1,3 (an example of reference signal # a) and RS2 and 3 (an example of reference signal # B) are both reference signals on subband #2, precoding matrix #1 and precoding matrix #2 corresponding to

RS #

1,3 and

RS #

2,3, respectively, may be the same.

As another example, precoding matrix #1 and precoding matrix #2 corresponding to reference signal # a and reference signal # B, respectively, on the same first frequency domain unit are different. The following description will take the first frequency domain unit as an example, which is a subband.

For example, as shown in fig. 5, precoding matrix #1 corresponding to

RS #

1,1 is different from precoding matrix #2 corresponding to

RS #

2,1; precoding matrix #1 corresponding to

RS #

1,2 is different from precoding matrix #2 corresponding to

RS #

2,2; … …; precoding matrix #1 corresponding to RS #1,K is different from precoding matrix #2 corresponding to RS #2,K.

Alternatively, the precoding matrix #1 corresponding to any one of the reference signals # a and the precoding matrix #2 corresponding to any one of the reference signals # B are different.

For example, as shown in fig. 5, precoding matrix #1 corresponding to

RS #

1,1 is different from precoding matrix #2 corresponding to

RS #

2,1 to RS #2,K, respectively; the precoding matrix #1 corresponding to

RS #

1,2 is different from the precoding matrix #2 corresponding to

RS #

2,1 to RS #2,K, respectively; … …; the precoding matrix #1 corresponding to RS #1,K is different from the precoding matrix #2 corresponding to

RS #

2,1 to RS #2,K, respectively.

Alternatively, the network device may also transmit multiple reference signals # C on time domain unit #3, multiple reference signals # D, … … on time domain unit #4, and so on. Time domain unit #3 is different from time domain unit #4, and time domain unit #3 and time domain unit #4 are different from time domain unit #2 and time domain unit #1.

In the following, taking the example that the network device transmits the reference signals in L time domain units, the precoding matrices corresponding to the reference signals in different time domain units will be described without loss of generality. It should be understood that the reference signals described hereinafter still satisfy that the precoding matrices respectively corresponding to the reference signals on at least two different first frequency domain units are different. The following description will be given taking an example in which the time domain unit is a subframe and the first frequency domain unit is a subband.

Assuming that the number of reference signals sent by the network device on each subframe is K, the reference signal sent by the network device on the kth RB of the l-th subframe is denoted as B _k,l X _k,l ，B _k,l And X _k,l K =1,2, …, K, L =1,2, …, L, respectively, is the precoding matrix and the reference signal before precoding.

In one implementation, the precoding matrices corresponding to any two reference signals carried on different subframes of the same subband are the same.

As an example, B _k,l ＝Ψ _m ，k∈C _m ，m＝1,2,…,M。

As another example, B _k,l ＝FΦ _mod(m,P+1) k∈C _m ,m＝1,2,…,M。

According to B in the two examples _k,l The expression of (A) indicates that B _k,l Is related only to the subscript k and not to the subscript l, i.e. to C to which the subscript k belongs _m B when the subscript L changes from 1 to L while remaining unchanged _k,l B remaining unchanged, i.e. corresponding to multiple reference signals carried on different sub-frames of the same sub-band _k,l Remain unchanged.

In another implementation, the precoding matrices respectively corresponding to at least two reference signals carried on different subframes of the same subband are different.

As an example, B _k,l ＝Ψ _m,l ，k∈C _m ，m＝1,2,…,M。

As another example, B _k,l ＝FΦ _mod(m+l,P+1) k∈C _m ,m＝1,2,…,M。

According to B in the above two examples _k,l The expression of (A) indicates that B _k,l Are related to both subscript k and subscript l, i.e. C to which subscript k belongs _m B is changed and/or the value of subscript l is changed _k,l May vary, i.e. B corresponding to a plurality of reference signals carried on different sub-frames of different sub-bands _k,l Are not identical.

S280, the terminal device generates PMI #2.

S290, the terminal device transmits PMI #2. Accordingly, in S290, the network device receives PMI #2.

PMI #2 is determined by the terminal apparatus based on the received plurality of reference signals # B. The PMI #2 is configured to indicate a plurality of codewords #2, the plurality of codewords #2 correspond to a plurality of second frequency domain units one to one, the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource, and the plurality of codewords #2 are configured to determine a downlink channel. The one-to-one correspondence of the plurality of codewords #2 with the plurality of second frequency domain units may be understood as that each codeword #2 is obtained by the terminal device based on the reference signal # B on the second frequency domain unit.

Specifically, the method in which the terminal device determines PMI #2 from the received reference signal # B and transmits PMI #2 to the network device may refer to the description about PMI #1 in S240. For the sake of brevity, the embodiments of the present application are not described in detail.

In the case where the method 200 performs S270 to S290, assuming that the channel is approximately unchanged in the time domain unit #1 and the time domain unit #2, the terminal device may determine the downlink channel in combination of the PMI #1 and the PMI #2 in S260.

As described above, the network device may send multiple reference signals # C on the time domain unit #3, and accordingly, the terminal device may measure the downlink channel according to the multiple reference signals # C and feed back PMI #3, PMI #3 for indicating codeword #3 to the network device; the network device may send a plurality of reference signals # D on the time domain unit #4, and accordingly, the terminal device may measure the downlink channel according to the plurality of reference signals # D, and feed back PMI #4, PMI #4 for indicating the codeword #4 … …, and so on to the network device. In this case, assuming that the downlink channel is approximately unchanged in a plurality of time domain units, in S250, the terminal device may determine the downlink channel by combining a plurality of PMIs.

The method for jointly determining a downlink channel provided in the embodiment of the present application is described below by taking an example in which a network device sends a reference signal on L time domain units without loss of generality. The following description will be given by taking an example in which the time domain unit is a subframe and the first frequency domain unit and the second frequency domain unit are RBs. It should be understood that the method described below assumes that the downlink channel is approximately constant over L subframes. In the case where the downlink channel is rapidly changed, the network device may determine the downlink channel based on the PMI #1 described above.

Assuming that the number of reference signals transmitted by the network device in each subframe is K, the signal received by the terminal device in the kth RB of the l subframe may be represented as:

Y _k,l ＝H _dl,k,l B _k,l X _k,l +Z _k,l (7)

wherein H _dl,k,l A downlink channel on the kth RB representing the l subframe, with dimension M _r ×M _t ；Z _k,l The representation represents interference noise with dimension M _r X P. The equivalent channel H of the kth RB of the l subframe can be obtained according to the formula (7) _dl,k,l B _k,l LS of (is) estimated as Y _k,l X _k,l ^-1 。

Optionally, in the case that the first frequency domain unit is a subband, according to the above description, the precoding matrices respectively corresponding to all reference signals in the same subband are the same, so the terminal device may further perform joint filtering and denoising processing on LS estimation results of all RBs in the same subband, and a finally obtained equivalent channel on the kth RB of the l subframe may be represented as

Further, the terminal device may determine a codeword of a kth RB of the ith subframe according to an equivalent channel on the kth RB of the ith subframe, and feed back the codeword to the network device through the PMI. Denote the code word of the kth RB of the l subframe as J _k,l The dimension is P multiplied by R, and R is the number of transmission layers. It can be understood that, in the case that precoding matrices respectively corresponding to reference signals on respective RBs of the l-th subframe are different, quantization feedback of codewords of the respective RBs of the l-th subframe should be independently performed.

Optionally, the terminal device may also perform quantization feedback based on the sub-bands, i.e., the second frequency domain unit may be a sub-band. The terminal equipment can determine the equivalent channel of the mth sub-band of the ith sub-band according to the equivalent channels of all RBs in the mth sub-band of the ith sub-band; and further, determining a code word of the mth subband of the ith subframe according to the equivalent channel of the mth subband of the ith subframe. The code word of the mth sub-band of the mth sub-frame is recorded as W _m,l The dimension is P multiplied by R, and R is the number of transmission layers. Precoding matrices different from each other with respect to reference signals on subbands of the l-th subframeIn this case, quantization feedback of codewords of each subband of the l-th subframe should be performed independently.

Further, make

Under the condition that the terminal equipment carries out quantization feedback based on sub-bands, J is enabled _k,l ＝W _m,l k∈C _m 。

Further, the network device may perform the following iterative operations:

wherein t _ larget _ eigvec () represents the first r largest eigenvectors, V _k,l,1 And

respectively represent

Left and right feature matrices of, i.e. obtained by SVD decomposition

Fig. 6 is a schematic flow chart diagram of a method 600 for channel measurement according to another embodiment of the present application. As shown in fig. 6, the method 600 may include S610 to S660. The steps in method 600 are described in detail below.

S610, the terminal equipment sends the uplink reference signal. Accordingly, in S610, the network device receives an uplink reference signal.

S620, the network equipment estimates an uplink channel according to the uplink reference signal and calculates a space frequency domain channel characteristic matrix of the uplink channel.

Specifically, the detailed description about S610 and S620 may refer to the above description about S210 and S220, and for brevity, will not be described in detail here.

S630, the network device transmits a plurality of reference signals # a. Accordingly, in S630, the terminal device receives a plurality of reference signals # a.

The multiple reference signals # a are reference signals in different first frequency domain units in the same time domain unit, and the time domain unit in which the multiple reference signals # a are located is hereinafter referred to as time domain unit # a. The plurality of reference signals # a may be precoded reference signals or non-precoded reference signals, which is not limited in this embodiment of the present application.

For example, each of the plurality of reference signals # a is a reference signal precoded by the precoding matrix #1, and the precoding matrix #1 corresponding to a different reference signal # a is the same. The precoding matrix #1 may be the fixed beam matrix F described above.

As described above, assuming that the number of reference signals # a is K, the reference signal # a transmitted by the network device on the kth RB may be denoted as B _k X _k . Wherein, B _k ＝F，k＝1,2,…,K。

The time domain unit #1 may be a radio frame (frame), a subframe (sub-frame), a slot (slot), etc., which is not limited in the embodiment of the present application, and the time domain unit #1 is a subframe as an example for description.

The first frequency domain unit may be a subband, an RB, an RBG, a PRG, and the like, which is not limited in this embodiment of the present application.

S640, the terminal device generates PMI #1.

S650, the terminal device transmits PMI #1. Accordingly, in S650, the network device receives PMI #1.

The PMI #1 is determined by the terminal apparatus based on the received plurality of reference signals # a and the weighting matrix #1. The PMI #1 is configured to indicate a plurality of code words #1, the plurality of code words #1 are configured to determine a downlink channel, the plurality of code words #1 correspond to weighted equivalent channels of a plurality of second frequency domain units one to one, the weighted equivalent channel of each second frequency domain unit is obtained according to the weighted matrix #1 corresponding to the second frequency domain unit, and the weighted matrices #1 corresponding to at least two different second frequency domain units are different, that is, the weighted equivalent channels of at least two different second frequency domain units are obtained according to different weighted matrices #1, and a source of the plurality of second frequency domain units and a source of the plurality of first frequency domain units belong to the same frequency domain resource. The one-to-one correspondence between the plurality of codewords #1 and the plurality of weighted equivalent channels of the second frequency domain unit can be understood as that each codeword #1 is obtained by the terminal device based on the reference signal # a on the second frequency domain unit.

After receiving the multiple reference signals # a transmitted by the network device, the terminal device may measure the downlink channel according to the multiple reference signals # a and estimate the equivalent channel of each RB. The method for estimating the equivalent channel of each RB by the terminal device is not limited in the embodiment of the present application, for example, the terminal device may estimate the equivalent channel of each RB by using a Least Square (LS) method.

For example, if each reference signal # a is a reference signal precoded by the fixed beam matrix F, then for the kth reference signal # a transmitted by the network device, the signal received by the terminal device may be represented as:

Y _k ＝H _dl,k B _k X _k +Z _k ，k＝1,2,…,K (7)

wherein H _dl,k Represents a downlink channel on the k RB with a dimension of M _r ×M _t ；Z _k The representation represents interference noise with dimension M _r ×P；B _k = F. The equivalent channel H of the kth RB can be obtained according to the formula (7) _dl,k B _k LS of is estimated as Y _k X _k ^-1 。

For another example, if each reference signal # a is a reference signal that is not precoded, the signal received by the terminal device for the kth reference signal # a transmitted by the network device may be represented as:

Y _k ＝H _dl,k X _k +Z _k ，k＝1,2,…,K (8)

the equivalent channel H of the kth RB can be obtained according to the formula (8) _dl,k LS of is estimated as Y _k X _k ^-1 。

Alternatively, since the precoding matrices #1 respectively corresponding to all the reference signals # a are the same, the terminal device may also perform joint filtering and denoising processing on LS estimation results of all RBs in the full band, and the resulting equivalent channel on the kth RB may be represented as

Or

Further, the terminal device obtains a weighted equivalent channel of each RB from the weighting matrix #1 and the equivalent channel of each RB.

The embodiment of the present application does not limit the weighting matrix #1.

As an example, if the reference signal # a is a reference signal precoded with a fixed beam matrix F, the weighting matrix #1 may be a MUB matrix.

For example, the weighting matrix #1 used to derive the weighted equivalent channel of the kth RB can be denoted as Φ _mod(k,P+1) . Wherein K =1,2, …, K, { Φ ₀ ,Φ ₁ ,…,Φ _P Denotes a set of MUB matrices with P +1 dimensions P × P, mod (a, b) denotes a modulo b operation on a. The weighted equivalent channel of the kth RB can be expressed as

B _k ＝F。

Further, the terminal device may determine the codeword #1 corresponding to the kth RB according to the weighted equivalent channel of the kth RB, which is recorded as

The dimension is P multiplied by R, and R is the number of transmission layers.

It is to be understood that in this example, weighted equivalent channels of different RBs are obtained from different weighting matrices #1, and thus codebook quantization for each RB should be performed independently.

Alternatively, the second frequency domain elements may be subbands, in which case the weighted equivalent channels for different subbands may be derived from different weighting matrices #1. The weighting matrix #1 corresponding to the mth subband may be expressed as: phi _mod(m,P+1) M =1,2, …, M is the number of subbands.

For example, the terminal device may determine an equivalent channel for the mth subband from equivalent channels of respective RBs within the mth subband,can be expressed as

Further, a weighted equivalent channel of the mth subband is obtained according to the weighting matrix #1 corresponding to the mth subband, and represents that

For another example, the terminal device may first obtain the weighted equivalent channel of each RB in the mth subband according to the weighting matrix #1 corresponding to the mth subband, and then obtain the weighted equivalent channel of the mth subband according to the weighted equivalent channel of each RB in the mth subband.

Further, the terminal device may obtain codeword #1 of mth subband according to the weighted equivalent channel of mth subband, which is denoted as W _m The dimension is P multiplied by R, and R is the number of transmission layers.

The method for determining the codeword #1 of each RB by the terminal device according to the weighted equivalent channel of each RB is not limited in the embodiment of the present application. For example, the terminal device may perform Singular Value Decomposition (SVD) on the weighted equivalent channel of each RB, and determine codeword #1 corresponding to the weighted equivalent channel of each RB.

The embodiment of the present application does not limit the way in which the terminal device determines PMI #1. For example, the terminal device may determine the PMI based on the port selection codebook. The port selection codebook may be, for example, a type II port selection codebook (type II port selection codebook) defined in the NR protocol. For more ways for determining the PMI #1 by the terminal device, reference may be made to the prior art, and for brevity, the embodiments of the present application are not described in detail.

S660, the network equipment determines a downlink channel according to the code word #1 of each RB and the space frequency domain channel characteristic matrix of the uplink channel.

Order to

with a representation dimension of M _t ×M _t The unit matrix of (2).

If the code word #1 fed back by the terminal equipment is

And the weighting matrix #1 is the MUB matrix, then order

If the code word #1 fed back by the terminal equipment is W _m And the weighting matrix #1 is the MUB matrix, let J _k ＝Φ _mod(m,P+1) W _m ，k∈C _m 。

Further, the network device may perform the following iterative operations:

wherein t _ larget _ eigvec () represents the first t largest eigenvectors, V _k,1 And

respectively represent

Left and right feature matrices, i.e. obtained by SVD decomposition

it should be understood that, in the process of determining the downlink channel, only the network device determines the downlink channel of each RB as an example for description, and the embodiment of the present application should not be limited in any way. For example, the above-mentioned formula of iterative operation and formula (6) may be appropriately modified to determine the downlink channel of each subband.

In the embodiment of the present application, by loading different weighting matrices #1 to equivalent channels of at least two different second frequency domain units, correlations of channels in different second frequency domain units can be reduced, and further, correlations of errors of quantization feedback performed by terminal equipment on codewords #1 in different second frequency domain units can be reduced, so that accuracy of reconstructing a downlink channel can be improved. In addition, according to the embodiment of the application, the downlink channel is reconstructed on the angle delay domain in a combined manner by utilizing the sparsity of the downlink channel on the angle delay domain, and then the channel of the angle delay domain is transformed to the spatial frequency domain, so that the complexity of the reconstructed downlink channel can be reduced, and the performance of the reconstructed downlink channel can be improved.

Optionally, the method 600 may further include S670 to S690.

S670, the network device transmits a plurality of reference signals # B. Accordingly, in S670, the terminal device receives a plurality of reference signals # B.

The multiple reference signals # B are reference signals in different first frequency domain units in the same time domain unit, and the time domain unit in which the multiple reference signals # B are located is hereinafter referred to as time domain unit #2. The plurality of reference signals # B may be precoded reference signals or non-precoded reference signals, which is not limited in this embodiment of the present application.

For example, each of the plurality of reference signals # B is a reference signal precoded by the precoding matrix #2, and the precoding matrix #2 corresponding to a different reference signal # B is the same. The precoding matrix #2 may be the fixed beam matrix F described above.

As described above, assuming that the number of reference signals # B is K, the reference signal # B transmitted by the network device on the kth RB can be denoted as B _k X _k . Wherein, B _k ＝F，k＝1,2,…,K。

Time domain unit #2 is different from time domain unit #1.

S680, the terminal device generates PMI #2.

S690, the terminal device transmits PMI #2. Accordingly, in S690, the network device receives PMI #2.

PMI #2 is determined by the terminal apparatus based on the received plurality of reference signals # B and weighting matrix #2. The PMI #2 is configured to indicate a plurality of code words #2, the plurality of code words #2 are configured to determine a downlink channel, the plurality of code words #2 correspond to weighted equivalent channels of a plurality of second frequency domain units one to one, the weighted equivalent channel of each second frequency domain unit is obtained according to the weighted matrix #2 corresponding to the second frequency domain unit, and the weighted matrices #2 corresponding to at least two different second frequency domain units are different, that is, the weighted equivalent channels of at least two different second frequency domain units are obtained according to different weighted matrices #2, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource. The one-to-one correspondence between the plurality of codewords #2 and the plurality of weighted equivalent channels of the second frequency domain unit can be understood as that each codeword #2 is obtained by the terminal device based on the reference signal # B on the second frequency domain unit.

For the description of the weighting matrix #2, reference may be made to the description of the weighting matrix #1 in S650, and for the method for the terminal device to generate and transmit the PMI #2 according to the received reference signal # B, reference may be made to the description of the PMI #1 in S650, and for brevity, details of the embodiments of the present application are not described in detail.

The following describes the relationship between the weighting matrix #1 and the weighting matrix #2. Note that, the weighting matrix #1 corresponding to the second frequency domain unit mentioned hereinafter represents: the terminal equipment is used for determining a weighting matrix of the weighting equivalent channel of the second frequency domain unit, and the terminal equipment determines the weighting equivalent channel according to the reference signal # A received on the second frequency domain unit and the weighting matrix # 1; the weighting matrix #2 corresponding to the second frequency domain unit referred to hereinafter represents: the terminal device is configured to determine a weighting matrix for the weighted equivalent channel for the second frequency domain element, and the terminal device determines the weighted equivalent channel based on the reference signal # a received on the second frequency domain element and the weighting matrix #1.

The embodiment of the present application does not limit the relationship between the weighting matrix #1 and the weighting matrix #2.

As an example, weight matrix #1 and weight matrix #2 corresponding to the same second frequency domain unit on different time domain units may be the same. The following description will be given taking the second frequency domain unit as an RB as an example.

For example, as shown in fig. 5, the terminal device may obtain an equivalent weighted channel of RB #1 from RS #1,1 (an example of reference signal # a) and weighting matrix #1 on RB #1, the terminal device may obtain an equivalent weighted channel of RB #1 from RS #2,1 (an example of reference signal # B) and weighting matrix #2 on RB #1, and weighting matrix #1 and weighting matrix #2 corresponding to RB #1 may be the same.

As another example, weighting matrix #1 and weighting matrix #2 corresponding to the same second frequency domain unit on different time domain units are different. The second frequency domain unit RB is explained as an example.

For example, as shown in fig. 5, the terminal device may obtain an equivalent weighted channel of RB #1 from RS #1,1 (an example of reference signal # a) and weighting matrix #1 on RB #1, may obtain an equivalent weighted channel of RB #1 from RS #2,1 (an example of reference signal # B) and weighting matrix #2 on RB #1, and may be different from weighting matrix #1 and weighting matrix #2 corresponding to RB #1.

Alternatively, the weighting matrix #1 corresponding to any one of the second frequency domain elements is different from the weighting matrix #2 corresponding to another any one of the second frequency domain elements.

For example, as shown in fig. 5, the weighting matrix #1 corresponding to RB #1 is different from the weighting matrix #2 corresponding to RB #1 to RB # K, respectively; the weighting matrix #1 corresponding to RB #2 is different from the weighting matrix #2 corresponding to RB #1 to RB # K, respectively; … …; the weighting matrix #1 corresponding to RB # K is different from the weighting matrix #2 corresponding to RB #1 to RB # K, respectively.

In a case where the method 600 performs S670 to S690, assuming that the channel is approximately unchanged in the time domain unit #1 and the time domain unit #2, the terminal apparatus may determine the downlink channel in association with the PMI #1 and the PMI #2 in S660.

In the following, taking the example that the network device transmits the reference signal on L time domain units without loss of generality, the weighting matrix corresponding to the second frequency domain unit on different time domain units is described. It should be understood that what is described below still satisfies that the weighting matrices corresponding to at least two different second frequency-domain units on the same time-domain unit are different. The second frequency domain unit is hereinafter explained as RB.

Assuming that the number of reference signals sent by the network device on each subframe is K, if the reference signals sent by the network device are not precoded, referring to the above formula (8), the equivalent channel of the kth RB of the l subframe obtained by the terminal device may be denoted as H _dl，k，l ＝Y _k，l X _k，l ^-1 (ii) a If the reference signal sent by the network device is precoded by the fixed beam matrix F, referring to the formula (7), the equivalent channel of the kth RB of the l subframe obtained by the terminal device can be recorded as H _dl,k,l B _k,l ＝＝Y _k,l X _k,l ^-1 ,B _k,l ＝F。

In one implementation, the weighting matrices corresponding to the same second frequency domain unit on different time domain units are the same.

As an example, the weighting matrix corresponding to the kth RB of the ith subframe may be expressed as: phi _mod(k,P+1) 。

As can be seen from the expression of the weighting matrix in the above example, the different values of the weighting matrix relate only to the subscript k and do not relate to the subscript L, i.e. in case the subscript k remains unchanged and the value of the subscript L varies from 1 to L, the weighting matrix remains unchanged, i.e. the weighting matrix corresponding to the same second frequency domain unit on different time domain units remains unchanged.

In another implementation, the weighting matrix #1 and the weighting matrix #2 corresponding to the same second frequency domain unit on different time domain units are different.

As an example, the weighting matrix corresponding to the kth RB of the ith subframe may be expressed as: phi _mod(k+l,P+1) 。

As can be known from the expression of the weighting matrix in the above example, different values of the weighting matrix are related to both the subscript k and the subscript l, that is, in the case that the subscript k changes and/or the value of the subscript l changes, the weighting matrix may change, that is, the weighting matrices corresponding to the same second frequency domain units on different time domain units are not completely the same.

Accordingly, the terminal apparatus can generate PMI #3 from a plurality of reference signals # C, PMI #4, … … from a plurality of reference signals # D, and the like. Further, assuming that the downlink channel is approximately unchanged in multiple time domain units, in S660, the terminal device may determine the downlink channel by combining multiple PMIs.

The method for jointly determining a downlink channel provided in the embodiment of the present application is described below by taking an example in which a network device sends a reference signal on L time domain units without loss of generality. The following description takes the case that the time domain unit is a subframe, and the first frequency domain unit and the second frequency domain unit are RBs, and the following description takes the case that the reference signal transmitted by the network device is a reference signal pre-coded by a fixed beam matrix. It should be understood that the method described below assumes that the downlink channel is approximately constant over L subframes. In case of a fast change of the downlink channel, the network device may determine the downlink channel based on the PMI #1 described above.

Y _k,l ＝H _dl,k,l B _k,l X _k,l +Z _k,l (9)

wherein H _dl,k,l A downlink channel on the kth RB representing the l subframe, with dimension M _r ×M _t ；Z _k,l The representation represents interference noise with dimension M _r ×P；B _k,l = F, K =1,2, …, K, L =1,2, …, L. The equivalent channel H of the kth RB of the l subframe can be obtained according to the formula (9) _dl,k,l B _k,l LS of is estimated as Y _k,l X _k,l ^-1 。

Optionally, since the precoding matrices respectively corresponding to all reference signals are the same, the terminal device may further perform joint filtering and noise reduction on LS estimation results of all RBs in the full band, and the finally obtained equivalent channel on the kth RB may be represented as

Further, taking the weighting matrix as the MUB matrix as an example, the terminal device may obtain an equivalent weighting channel of the kth RB of the ith subframe:

further, the terminal device may determine a codeword of a kth RB of the l subframe according to the weighted equivalent channel on the kth RB of the l subframe, and feed back the codeword to the network device through the PMI. Record the code word of the k RB of the l subframe as

The dimension is P multiplied by R, and R is the number of transmission layers. It is to be understood that, in the case where the weighting matrices corresponding to the RBs of the ith subframe are different, the quantization feedback of the codewords of the RBs of the ith subframe should be performed independently.

Optionally, the terminal device may also perform quantization feedback based on the sub-bands, i.e., the second frequency domain unit may be a sub-band. The terminal device may determine the equivalent channel of the mth sub-band of the lth sub-band according to the equivalent channels of all RBs in the mth sub-band of the lth sub-band; further, determining an equivalent weighted channel of the mth sub-band of the lth sub-frame according to the equivalent channel of the mth sub-band of the lth sub-frame; and further, determining a code word of the mth subband of the ith subframe according to the weighted equivalent channel of the mth subband of the ith subframe. The code word of the mth sub-band of the mth sub-frame is recorded as W _m,l The dimension is P multiplied by R, and R is the number of transmission layers. When the weighted code matrix corresponding to each sub-band of the ith sub-frame is different, the quantization feedback of the code word of each sub-band of the ith sub-frame should be performed independently.

Further, let

Order to

Or, in the case that the terminal device performs quantization feedback based on sub-bands, let J _k,l ＝Φ _mod(m+l,P+1) W _m,l k∈C _m 。

Further, the network device may perform the following iterative operations:

wherein t _ larget _ eigvec () represents the first r largest eigenvectors, V _k,l,1 And with

Respectively represent

Left and right feature matrices of, i.e. obtained by SVD decomposition

It should also be understood that, in the foregoing embodiments, the sequence numbers of the processes do not imply an execution sequence, and the execution sequence of the processes should be determined by functions and internal logic of the processes, and should not constitute any limitation on the implementation process of the embodiments of the present application.

The method for channel measurement provided by the embodiment of the present application is described in detail above with reference to fig. 2 to fig. 6. Hereinafter, the communication device according to the embodiment of the present application will be described in detail with reference to fig. 7 to 9.

Fig. 7 is a schematic block diagram of a communication device provided in an embodiment of the present application. As shown, the communication device 1000 may include a transceiving unit 1200 and a processing unit 1100.

In one possible design, the communication apparatus 1000 may correspond to the terminal device in the above method embodiment, and may be, for example, the terminal device or a component (e.g., a circuit, a chip, or a system of chips, etc.) configured in the terminal device.

Specifically, the communication apparatus 1000 may correspond to the terminal device in the method 200 or the method 600 according to the embodiment of the present application, and the communication apparatus 1000 may include a unit for performing the method performed by the terminal device in the method 200 or the method 600 in fig. 2 or fig. 6. Also, the units and other operations and/or functions in the communication device 1000 are respectively for realizing the corresponding flows of the method 200 in fig. 2 or the method 600 in fig. 6.

When the communication device 1000 is configured to execute the method 200 in fig. 2, the transceiver 1200 may be configured to execute S210, S230, and S250 in the method 200, and the processing unit 1100 may be configured to execute S240 in the method 200.

When the communication device 1000 is configured to perform the method 600 in fig. 6, the transceiver unit 1200 may be configured to perform S610, S630, and S650 in the method 600, and the processing unit 1100 may be configured to perform S640 in the method 600.

It should be understood that the specific processes of the units for executing the corresponding steps are already described in detail in the above method embodiments, and therefore, for brevity, detailed descriptions thereof are omitted.

It should also be understood that when the communication apparatus 1000 is a terminal device, the transceiver 1200 in the communication apparatus 1000 may be implemented by a transceiver, for example, may correspond to the transceiver 2020 in the communication apparatus 2000 illustrated in fig. 8 or the transceiver 3020 in the terminal device 3000 illustrated in fig. 9, and the processing unit 1100 in the communication apparatus 1000 may be implemented by at least one processor, for example, may correspond to the processor 2010 in the communication apparatus 2000 illustrated in fig. 8 or the processor 3010 in the terminal device 3000 illustrated in fig. 9.

It should also be understood that, when the communication device 1000 is a chip or a chip system configured in a terminal device, the transceiver unit 1200 in the communication device 1000 may be implemented by an input/output interface, a circuit, or the like, and the processing unit 1100 in the communication device 1000 may be implemented by a processor, a microprocessor, an integrated circuit, or the like integrated on the chip or the chip system.

In another possible design, the communication apparatus 1000 may correspond to the network device in the above method embodiment, and may be, for example, a network device or a component (e.g., a circuit, a chip, a system of chips, or the like) configured in the network device.

Specifically, the communication apparatus 1000 may correspond to the network device in the method 200 or the method 600 according to the embodiment of the present application, and the communication apparatus 1000 may include a unit for performing the method performed by the network device in the method 200 or the method 600 in fig. 2 or fig. 6. Also, the units and other operations and/or functions described above in the communication device 1000 are respectively for implementing the corresponding flows of the method 200 in fig. 2 or the method 600 in fig. 6.

Wherein, when the communication device 1000 is used to execute the method 200 in fig. 2, the transceiver 1200 may be used to execute S210, S230, and S250 in the method 200, and the processing unit 1100 may be used to execute S220 and S260 in the method 200.

When the communication device 1000 is configured to perform the method 600 in fig. 6, the transceiver unit 1200 may be configured to perform S610, S630, and S650 in the method 600, and the processing unit 1100 may be configured to perform S620 and S660 in the method 600.

It is also to be understood that when the communication apparatus 1000 is a network device, the transceiver unit 1200 in the communication apparatus 1000 may be implemented by a transceiver, for example, may correspond to the transceiver 2020 in the communication apparatus 2000 shown in fig. 8 or the RRU 4100 in the base station 4000 shown in fig. 10, and the processing unit 1100 in the communication apparatus 1000 may be implemented by at least one processor, for example, may correspond to the processor 2010 in the communication apparatus 2000 shown in fig. 8 or the processing unit 4200 or the processor 4202 in the base station 4000 shown in fig. 10.

It should also be understood that, when the communication device 1000 is a chip or a system of chips configured in a network device, the transceiver unit 1200 in the communication device 1000 may be implemented by an input/output interface, a circuit, etc., and the processing unit 1100 in the communication device 1000 may be implemented by a processor, a microprocessor, an integrated circuit, etc., integrated on the chip or the system of chips.

Fig. 8 is another schematic block diagram of a communication device 2000 provided in an embodiment of the present application. As shown in fig. 8, the communications device 2000 includes a processor 2010, a transceiver 2020, and a memory 2030. Wherein the processor 2010, the transceiver 2020, and the memory 2030 are in communication with each other via the internal connection path, the memory 2030 is configured to store instructions, and the processor 2010 is configured to execute the instructions stored in the memory 2030 to control the transceiver 2020 to transmit and/or receive signals.

It should be understood that the communication device 2000 may correspond to the terminal device in the above method embodiments, and may be configured to perform each step and/or flow performed by the network device or the terminal device in the above method embodiments. Alternatively, the memory 2030 may include a read-only memory and a random access memory, and provide instructions and data to the processor. The portion of memory may also include non-volatile random access memory. The memory 2030 may be a separate device or may be integrated into the processor 2010. The processor 2010 may be configured to execute the instructions stored in the memory 2030, and when the processor 2010 executes the instructions stored in the memory, the processor 2010 is configured to execute the steps and/or processes of the method embodiments corresponding to the network device or the terminal device.

Optionally, the communication device 2000 is the terminal device in the previous embodiment.

Optionally, the communication device 2000 is a network device in the foregoing embodiment.

The transceiver 2020 may include a transmitter and a receiver, among other things. The transceiver 2020 may further include one or more antennas. The processor 2010 and the memory 2030 and the transceiver 2020 may be devices integrated on different chips. For example, the processor 2010 and the memory 2030 may be integrated in a baseband chip and the transceiver 2020 may be integrated in a radio frequency chip. The processor 2010 and the memory 2030 and the transceiver 2020 may also be integrated devices on the same chip. This is not a limitation of the present application.

Alternatively, the communication device 2000 is a component configured in a terminal device, such as a circuit, a chip system, and the like.

Alternatively, the communication device 2000 is a component configured in a network device, such as a circuit, a chip system, and the like.

The transceiver 2020 may also be a communication interface, such as an input/output interface, a circuit, or the like. The transceiver 2020 may be integrated with the processor 2010 and the memory 2030 on the same chip, such as a baseband chip.

Fig. 9 is a schematic structural diagram of a terminal device 3000 according to an embodiment of the present application. The terminal device 3000 can be applied to a system as shown in fig. 1, and performs the functions of the terminal device in the above method embodiments. As shown, the terminal device 3000 includes a processor 3010 and a transceiver 3020. Optionally, the terminal device 3000 further includes a memory 3030. The processor 3010, the transceiver 3020 and the memory 3030 may communicate with each other via an internal connection path to transmit control and/or data signals, the memory 3030 is used to store a computer program, and the processor 3010 is used to call and run the computer program from the memory 3030 to control the transceiver 3020 to transmit and receive signals. Optionally, the terminal device 3000 may further include an antenna 3040, configured to send uplink data or uplink control signaling output by the transceiver 3020 through a wireless signal.

The processor 3010 and the memory 3030 may be combined into a processing device, and the processor 3010 is configured to execute the program code stored in the memory 3030 to implement the functions described above. In particular, the memory 3030 may be integrated with the processor 3010 or may be separate from the processor 3010. The processor 3010 may correspond to the processing unit 1100 of fig. 7 or the processor 2010 of fig. 8.

The transceiver 3020 described above may correspond to the transceiver unit 1200 in fig. 7 or the transceiver 2020 in fig. 8. The transceiver 3020 may include a receiver (or receiver, receiving circuit) and a transmitter (or transmitter, transmitting circuit). Wherein the receiver is used for receiving signals, and the transmitter is used for transmitting signals.

It should be understood that the terminal device 3000 shown in fig. 9 can implement various processes involving the terminal device in the method embodiments shown in fig. 2 or fig. 6. The operations and/or functions of the modules in the terminal device 3000 are respectively for implementing the corresponding flows in the above method embodiments. Reference may be made specifically to the description of the above method embodiments, and a detailed description is appropriately omitted herein to avoid redundancy.

The processor 3010 may be configured to perform the actions implemented by the terminal device in the foregoing method embodiments, and the transceiver 3020 may be configured to perform the actions transmitted to or received from the network device by the terminal device in the foregoing method embodiments. Please refer to the description of the previous embodiment of the method, which is not repeated herein.

Optionally, the terminal device 3000 may further include a power supply 3050 for supplying power to various components or circuits in the terminal device.

In addition to this, in order to make the functions of the terminal device more complete, the terminal device 3000 may further include one or more of an input unit 3060, a display unit 3070, an audio circuit 3080, a camera 3090, a sensor 3100, and the like, and the audio circuit may further include a speaker 3082, a microphone 3084, and the like.

Fig. 10 is a schematic structural diagram of a network device provided in the embodiment of the present application, which may be a schematic structural diagram of a base station, for example. The base station 4000 may be applied to the system shown in fig. 1, and performs the functions of the network device in the method embodiment described above. As shown, the base station 4000 may include one or more radio frequency units, such as a Remote Radio Unit (RRU) 4100 and one or more baseband units (BBUs) (also referred to as Distributed Units (DUs)) 4200. The RRU 4100 may be referred to as a transceiver unit, and may correspond to the transceiver unit 1200 in fig. 7 or the transceiver 2020 in fig. 8. Optionally, the RRU 4100 may also be referred to as a transceiver, transceiver circuitry, or transceiver, etc., which may include at least one antenna 4101 and a radio frequency unit 4102. Optionally, the RRU 4100 may include a receiving unit and a sending unit, where the receiving unit may correspond to a receiver (or called receiver and receiving circuit), and the sending unit may correspond to a transmitter (or called transmitter and transmitting circuit). The RRU 4100 is mainly used for receiving and transmitting radio frequency signals and converting radio frequency signals and baseband signals, for example, for sending indication information to a terminal device. The BBU 4200 is mainly used for performing baseband processing, controlling a base station, and the like. The RRU 4100 and the BBU 4200 may be physically disposed together or may be physically disposed separately, that is, distributed base stations.

The BBU 4200 is a control center of the base station, and may also be referred to as a processing unit, and may correspond to the processing unit 1100 in fig. 7 or the processor 2010 in fig. 8, and is mainly configured to perform baseband processing functions, such as channel coding, multiplexing, modulation, spreading, and the like. For example, the BBU (processing unit) may be configured to control the base station to perform an operation procedure related to the network device in the foregoing method embodiment, for example, to generate the foregoing indication information.

In an example, the BBU 4200 may be formed by one or more boards, and the multiple boards may collectively support a radio access network of a single access system (e.g., an LTE network), or may respectively support radio access networks of different access systems (e.g., an LTE network, a 5G network, or other networks). The BBU 4200 further includes a memory 4201 and a processor 4202. The memory 4201 is used to store necessary instructions and data. The processor 4202 is configured to control the base station to perform necessary actions, for example, to control the base station to perform the operation procedure related to the network device in the above method embodiment. The memory 4201 and the processor 4202 may serve one or more boards. That is, the memory and processor may be provided separately on each board. Multiple boards may share the same memory and processor. In addition, each single board can be provided with necessary circuits.

It should be understood that the base station 4000 shown in fig. 10 can implement various processes involving network devices in the method embodiments shown in fig. 2 or fig. 6. The operations and/or functions of the respective modules in the base station 4000 are respectively to implement the corresponding flows in the above-described method embodiments. Reference may be made specifically to the description of the above method embodiments, and a detailed description is appropriately omitted herein to avoid redundancy.

The BBU 4200 described above may be used to perform actions described in the previous method embodiments that are implemented internally by the network device, while the RRU 4100 may be used to perform actions described in the previous method embodiments that the network device sends to or receives from the terminal device. Please refer to the description of the previous embodiment of the method, which is not repeated herein.

It should be understood that the base station 4000 shown in fig. 10 is only one possible form of network device, and should not limit the present application in any way. The method provided by the application can be applied to network equipment in other forms. For example, includes an AAU, and may also include CUs and/or DUs, or includes a BBU and an Adaptive Radio Unit (ARU), or a BBU; the network device may also be a Customer Premise Equipment (CPE) or other forms, and the present application is not limited to a specific form of the network device.

Wherein the CU and/or DU may be configured to perform the actions described in the previous method embodiments that are implemented internally by the network device, and the AAU may be configured to perform the actions described in the previous method embodiments that the network device transmits to or receives from the terminal device. Please refer to the description of the previous embodiment of the method, which is not repeated herein.

The present application further provides a processing apparatus, which includes at least one processor, and the at least one processor is configured to execute a computer program stored in a memory, so that the processing apparatus executes the method performed by the terminal device or the network device in any of the above method embodiments.

An embodiment of the present application further provides a processing apparatus, which includes a processor and a communication interface. The communication interface is coupled with the processor. The communication interface is used for inputting and/or outputting information. The information includes at least one of instructions and data. The processor is configured to execute the computer program, so as to enable the processing device to execute the method performed by the terminal device or the network device in any of the method embodiments.

An embodiment of the present application further provides a processing apparatus, which includes a processor and a memory. The memory is used for storing a computer program, and the processor is used for calling and running the computer program from the memory so as to enable the processing device to execute the method executed by the terminal device or the network device in any method embodiment.

It is to be understood that the processing means described above may be one or more chips. For example, the processing device may be a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), a system on chip (SoC), a Central Processing Unit (CPU), a Network Processor (NP), a digital signal processing circuit (DSP), a Microcontroller (MCU), a Programmable Logic Device (PLD), or other integrated chips.

In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or instructions in the form of software. The steps of a method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in a processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and combines hardware thereof to complete the steps of the method. To avoid repetition, it is not described in detail here.

It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip having signal processing capability. In implementation, the steps of the above method embodiments may be performed by integrated logic circuits of hardware in a processor or by instructions in the form of software. The processor described above may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules may be located in ram, flash, rom, prom, or eprom, registers, etc. as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and combines hardware thereof to complete the steps of the method.

It will be appreciated that the memory in the embodiments of the subject application can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The non-volatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable PROM (EEPROM), or a flash memory. Volatile memory can be Random Access Memory (RAM), which acts as external cache memory. By way of example, and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), SLDRAM (synchronous DRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

According to the method provided by the embodiment of the present application, the present application further provides a computer program product, which includes: computer program code which, when run on a computer, causes the computer to perform the method performed by the terminal device or the method performed by the network device in the embodiment shown in fig. 2 or fig. 6.

According to the method provided by the embodiment of the present application, the present application further provides a computer-readable storage medium, which stores program codes, and when the program codes are run on a computer, the computer is caused to execute the method executed by the terminal device or the method executed by the network device in the embodiment shown in fig. 2 or fig. 6.

According to the method provided by the embodiment of the present application, the present application further provides a system, which includes the foregoing one or more terminal devices and one or more network devices.

The network device in the foregoing device embodiments completely corresponds to the terminal device and the network device or the terminal device in the method embodiments, and the corresponding module or unit executes the corresponding steps, for example, the communication unit (transceiver) executes the steps of receiving or transmitting in the method embodiments, and other steps besides transmitting and receiving may be executed by the processing unit (processor). The functions of the specific elements may be referred to in the respective method embodiments. The number of the processors may be one or more.

In the above embodiments, the terminal device may be taken as an example of the receiving device, and the network device may be taken as an example of the sending device. This should not be construed as limiting the application in any way. For example, the transmitting device and the receiving device may both be terminal devices or the like. The present application is not limited to a specific type of the transmitting device and the receiving device.

As used in this specification, the terms "component," "module," "system," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between 2 or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from two components interacting with another component in a local system, distributed system, and/or across a network such as the internet with other systems by way of the signal).

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of channel measurement, comprising:

receiving a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit, wherein the plurality of reference signals are respectively precoded by precoding matrixes corresponding to the first frequency domain units, and the precoding matrixes corresponding to at least two different first frequency domain units in the plurality of first frequency domain units are different;

generating a Precoding Matrix Indicator (PMI) based on the plurality of reference signals, wherein the PMI is used for indicating a plurality of code words corresponding to a plurality of second frequency domain units, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource, and the plurality of code words are used for determining a downlink channel;

and sending the PMI.

2. A method of channel measurement, comprising:

sending a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit, wherein the plurality of reference signals are respectively precoded by precoding matrixes corresponding to the first frequency domain units where the plurality of reference signals are located, and precoding matrixes corresponding to at least two different first frequency domain units in the plurality of first frequency domain units are different;

receiving a Precoding Matrix Indicator (PMI), wherein the PMI is used for indicating code words corresponding to a plurality of second frequency domain units, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource;

and determining a downlink channel according to the plurality of code words and the space frequency domain channel characteristic matrix of the uplink channel.

3. The method of claim 2, wherein the determining the downlink channel according to the plurality of codewords and the space-frequency domain channel characteristic matrix of the uplink channel comprises:

obtaining a first downlink channel according to the plurality of code words and the space frequency domain channel characteristic matrix, wherein the first downlink channel is an angle time delay domain channel;

and obtaining a second downlink channel according to the first downlink channel and the space frequency domain channel characteristic matrix, wherein the second downlink channel is a space frequency domain channel.

4. The method according to any of claims 1 to 3, characterized in that the precoding matrix is a random semi-unitary matrix.

5. The method according to any of claims 1 to 3, characterized in that the precoding matrix is a product of a fixed beam matrix, which is a semi-unitary matrix with different columns having the same beam pattern, and a mutual unbiased base MUB matrix.

6. The method of any of claims 1 to 5, wherein the time domain unit is a subframe, wherein the first frequency domain unit is a resource block, RB, or subband, and wherein the second frequency domain unit is an RB, or subband.

7. A method of channel measurement, comprising:

receiving a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit;

generating a Precoding Matrix Indicator (PMI) based on the plurality of reference signals and the weighting matrix, wherein the PMI is used for indicating a plurality of code words corresponding to the weighting equivalent channels of the plurality of second frequency domain units, the plurality of code words are used for determining a downlink channel, the weighting equivalent channel of each second frequency domain unit is obtained according to the weighting matrix corresponding to the second frequency domain unit, the weighting matrices corresponding to at least two different second frequency domain units in the plurality of second frequency domain units are different, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource;

and sending the PMI.

8. A method of channel measurement, comprising:

transmitting a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit;

receiving a Precoding Matrix Indicator (PMI), wherein the PMI is used for indicating a plurality of code words corresponding to weighted equivalent channels of a plurality of second frequency domain units, the plurality of code words are used for determining a downlink channel, the weighted equivalent channel of each second frequency domain unit is obtained according to the weighted matrix corresponding to the second frequency domain unit, the weighted matrices corresponding to at least two different second frequency domain units in the plurality of second frequency domain units are different, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource;

9. The method of claim 8, wherein the determining the downlink channel according to the plurality of codewords and the space-frequency domain channel characteristic matrix of the uplink channel comprises:

10. The method according to any of claims 7 to 9, wherein the plurality of reference signals are each precoded by a fixed beam matrix, which is a semi-unitary matrix with different columns having the same beam pattern;

the weighting matrices are mutually unbiased basis MUB matrices.

11. The method of any of claims 7 to 10, wherein the time-domain unit is a subframe, wherein the first frequency-domain unit is a resource block, RB, or subband, and wherein the second frequency-domain unit is an RB or subband.

12. A communications apparatus, comprising: a transceiving unit and a processing unit, wherein,

the receiving and sending unit is used for receiving a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit, and the plurality of reference signals are respectively precoded by precoding matrixes corresponding to the first frequency domain units, wherein the precoding matrixes corresponding to at least two different first frequency domain units in the plurality of first frequency domain units are different;

the processing unit is configured to generate a precoding matrix indicator PMI based on the plurality of reference signals, where the PMI is configured to indicate a plurality of codewords corresponding to a plurality of second frequency domain units, the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource, and the plurality of codewords are used to determine a downlink channel;

the transceiver unit is further configured to transmit the PMI.

13. A communications apparatus, comprising: a transceiving unit and a processing unit, wherein,

the receiving and sending unit is used for sending a plurality of reference signals on a plurality of first frequency domain units in the same time domain unit, the plurality of reference signals are respectively precoded by precoding matrixes corresponding to the first frequency domain units, wherein the precoding matrixes corresponding to at least two different first frequency domain units in the plurality of first frequency domain units are different;

the transceiver unit is further configured to receive a Precoding Matrix Indicator (PMI), where the PMI is used to indicate a plurality of codewords corresponding to a plurality of second frequency domain units, and the plurality of second frequency domain units belong to the same frequency domain resource as the plurality of first frequency domain units;

the processing unit is configured to determine a downlink channel according to the multiple codewords and the spatial frequency domain channel feature matrix of the uplink channel.

14. The communication device according to claim 13, wherein the processing unit is specifically configured to:

obtaining a first downlink channel according to the multiple code words and the space frequency domain channel characteristic matrix, wherein the first downlink channel is an angle time delay domain channel;

15. Communication device according to any of claims 12 to 14, wherein the precoding matrix is a random semi-unitary matrix.

16. Communication device according to any of claims 12 to 14, wherein the precoding matrix is a product of a fixed beam matrix, which is a semi-unitary matrix with different columns having the same beam pattern, and a mutual unbiased base, MUB, matrix.

17. A communication apparatus according to any of claims 12 to 16, wherein the time domain units are sub-frames, the first frequency domain units are resource blocks, RBs, or sub-bands, and the second frequency domain units are RBs or sub-bands.

18. A communications apparatus, comprising: a transceiving unit and a processing unit, wherein,

the transceiver unit is configured to receive multiple reference signals in multiple first frequency domain units in the same time domain unit;

the processing unit is configured to generate a precoding matrix indicator PMI based on the plurality of reference signals and the weighting matrix, where the PMI is configured to indicate a plurality of codewords corresponding to a plurality of second frequency domain units, the codewords are used to determine a downlink channel, the weighted equivalent channels of the plurality of second frequency domain units are obtained according to the weighting matrices corresponding to the second frequency domain units, the weighting matrices corresponding to at least two different second frequency domain units in the plurality of second frequency domain units are different, and the plurality of second frequency domain units and the plurality of first frequency domain units belong to the same frequency domain resource;

the transceiver unit is further configured to transmit the PMI.

19. A communications apparatus, comprising: a transceiving unit and a processing unit, wherein,

the transceiver unit is configured to send multiple reference signals in multiple first frequency domain units in the same time domain unit;

the transceiver unit is further configured to receive a precoding matrix indicator PMI, where the PMI is configured to indicate multiple codewords corresponding to weighted equivalent channels of multiple second frequency domain units, where the multiple codewords are used to determine a downlink channel, where the weighted equivalent channels of the multiple second frequency domain units are obtained according to weighting matrices corresponding to the second frequency domain units, where the weighting matrices corresponding to at least two different second frequency domain units in the multiple second frequency domain units are different, and the multiple second frequency domain units and the multiple first frequency domain units belong to the same frequency domain resource;

20. The communications apparatus as claimed in claim 19, wherein the processing unit is specifically configured to:

21. A communication apparatus according to any of claims 18 to 20, wherein the plurality of reference signals are each precoded by a fixed beam matrix, the fixed beam matrix being a semi-unitary matrix with different columns having the same beam pattern;

the weighting matrices are mutually unbiased basis MUB matrices.

22. A communication apparatus according to any of claims 18 to 21, wherein the time domain unit is a sub-frame, the first frequency domain unit is a resource block, RB, or sub-band, and the second frequency domain unit is an RB or sub-band.

23. A communications apparatus comprising at least one processor configured to perform the method of any one of claims 1-11.

24. A computer-readable medium, comprising a computer program which, when run on a computer, causes the computer to perform the method of any one of claims 1 to 11.